Friendly response to logged-in user landing on user/reset

Problem/Motivation

For as long as I can remember, you get this error message, if you generate a one-time login link with Drush (for example /user/reset/1/1666288377/Wyf8bv[...]06_15sWg/login) and open it, if you are already logged in:

Access denied

You are not authorized to access this page

I know, we have all gotten used to this and accepted it (also me) but a few minutes ago, it dawned on me: It doesn't have to be like that. So hopefully the message can be updated from the current error message, to something meaningful and positive.

You can also generate a one-time login link via /user/password, but I am not sure if that link logs you out, and forwards to reset password form?

So this might be mainly a Drush issue, but since so many of us use Drush, many of us probably encounter this again and again, warranting action, in my opinion.

Steps to reproduce

1. Log in
2. Generate a one-time login link with Drush, open it and see the error message

Proposed resolution

Show a friendly and welcoming message, in stead of an error, for example:

Welcome back

You just used a one-time login link, but you were already logged in.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet